Research is progressing in four major areas. First, the role of vasoactive intestinal polypeptide (VIP) in pancreatic cholera syndrome is studied by investigating transport changes induced by the secretagogue in a dog model (isolated intestinal loop). Second, the physiological action of Na ions-K ions ATPase in intestinal absorption and secretion in evaluated in vivo (dog). ATPase activity is experimentally reduced by administration of ouabain directly into the superior mesenteric artery. Third, the function of the colon in the three major types of diarrhea (osmotic diarrhea, secretory diarrhea and steatorrhea) is investigated in healthy subjects by infusing large amounts of fluids into the cecum (containing electrolytes, glucose and fatty acids, respectively) and analyzing fecal output. Fourth, the influence of vagus nerve on intestinal secretion is studied by a modified sham feeding technique in humans. BIBLIOGRAPHIC REFERENCES: Krejs, G. J., Seelig, L. L., and Fordtran, J. S.: Effect of protonated 2,4,6-triaminopyrimidine (TAP plus), a "Tight Junction Blocker", on intestinal transport in dog ileum in vivo. Gastroenterology 72:685-691, 1977. Krejs, G. J., Walsh, J. H., Morawski, S. G., and Fordtran, J. S.: Intractable diarrhea: Intestinal perfusion studies and plasma VIP concentrations in patients with pancreatic cholera syndrome and surreptitious ingestion of laxatives and diuretics. Amer. J. Dig. Dis. 22:280-292, 1977.